This invention relates to detection of compounds such as explosives by their presence on surfaces. In particular, it concerns collection of compounds by wiping of trace amounts from surfaces with hand-coverings followed by rapid analysis of the collected compounds.
Various methods are known for acquiring and analyzing samples in order to detect compounds such as explosives concealed in luggage or other containers and whose presence in trace amounts on surfaces may indicate contact by a person who has handled such compounds. For example, U.S. Pat. No. 4,909,090, assigned to the assignee of the present invention and whose disclosure is incorporated herein by this reference to that patent, discloses a hand-operable vapor sampling probe which in a surface sampling mode heats and directs jets of air onto surfaces to produce/dislodge vapors of drugs or explosives. The vapors are drawn over, and trapped on, collector surfaces in the probe, then are subsequently desorbed and analyzed.
Another technique, referred to in U.S. Pat. No. 4,788,039, involves use of dry filter paper as a sampling device to acquire samples, as by application of the filter paper against the fingertips of a person suspected of handling explosives. Two chemical reagents are then applied in succession to the filter paper to check for specific explosives.
Although the above-noted detection equipment and methods are useful, additional improvements in speed and flexibility are desirable for certain detection applications. For example, the use of a piece of filter paper or the sampling probe of U.S. Pat. No. 4,909,090 to check multiple objects of different sizes and shapes in a room would require considerable time and effort. Moreover, some surface portions of certain objects (e.g., a telephone, radio, door handle) could be incompletely sampled during normal use of the equipment and procedures described in these patents. These prior art techniques may thus be less than optimum where speed and completeness of sampling are of particular importance, as in high volume strategic areas such as airport terminals. In addition, a sampling probe which can both heat samples and puff and draw air over collector surfaces may be rather complex and bulky for ease of operation.
Accordingly, it is an object of the invention to provide an improved method for rapid checking of surfaces for the presence of specific compounds.
It is a particular object of the invention to provide a method for rapid, selective detection of trace amounts of explosives on surfaces.
It is an object of the invention to provide an improved method for collecting samples of specific compounds such as explosives and drugs from surfaces without the use of heat from a sampling probe.